[coreboot] SeaBIOS and the Geode LX framebuffer
scrocker at ampltd.com
Mon Oct 6 17:55:19 CEST 2008
Jordan Crouse wrote:
> On 06/10/08 16:24 +0100, Stephen Crocker wrote:
>> Jordan Crouse wrote:
>>> On 06/10/08 15:31 +0100, Stephen Crocker wrote:
>>>> Carl-Daniel Hailfinger wrote:
>>>>> On 03.10.2008 12:29, Stephen Crocker wrote:
>>>>>> Is there a way of getting VGA support with SeaBIOS on the AMD Geode LX
>>>>>> framebuffer? I have successfully built and tested a BIOS image that
>>>>>> appears to boot into DOS but the lack of display means that it is of
>>>>>> little use. Is there a VGA ROM image that I can include?
>>>>> You'd need a VGA emulation VSA and AFAIK that piece of software is not
>>>>> available as open source due to an interesting rights situation.
>>>> How much of this is handled in AMD's binary VSA module? I have been
>>>> looking through both the AMD and OpenVSA source and it looks as if the
>>>> lxvg module is supposed to handle VGA SMIs but I cannot find where this
>>>> is actually done.
>>> None of it - the VGA is actually a seperate component under difference
>>> licensing. Thats why you don't see it in the VSA code.
>> This is quite an important point, as a lot of programs access the I/O
>> ports and framebuffer directly. A VGA BIOS would be able to handle the
>> functions provided by INT 10 but in my experience, that would not be
> Not sure what you are trying to say here - beyond the PCI emulation, the
> VSA neither grants nor restricts access to the graphics hardware. This
> is why we have been able to get away without VGA up to this point - both
> the libpayload driver and the kernel framebuffer drivers are perfectly
> good replacements for standard int 10 behavior.
I was under the impression that the Geode display hardware does not
provide the standard I/O ports and memory areas exposed by standard VGA
hardware (eg. ports 3d4/3d5 and segment A000) and that this was all
emulated in the VSA using SMIs. Am I incorrect about this?
More information about the coreboot